quickly spreading to several tribes of Plains Indians. In this case, there can not be the least doubt as the events are a matter of history. Again, at the present day the mescal ceremonies are working their way up from the south among the Plains tribes; this is also a matter of history. In addition to these absolute examples of cultural borrowing, we have cases like the grass dance ceremony, now found in all parts of the area. We have the testimony of several tribes to the effect that this ceremony first originated with the Pawnee. The Teton-Dakota claim to have obtained it directly from the Pawnee about 1870; the Arapaho and Gros Ventre claim to have borrowed it from the Dakota; the Gros Ventre claim to have taught it to the Blackfoot about 1883. While these statements of the Indians need not be taken as absolutely correct, their significance can not be ignored. There are still other traits like the sun dance which are found in the same essential forms among many tribes of the area, but concerning which the Indians have no definite historical knowledge. In this class also must be placed the more objective traits, like tipis and decorative designs. Now, since we have direct historic evidence of borrowing in some cases, the testimony of Indians in others, and still others in which we see all the secondary signs of borrowing, it must be admitted that a strong case has been made for the spread of culture by inter-tribal borrowing.
While borrowing will thus account for the distribution of traits, it can not answer the question as to their origin. For each trait we have a separate problem, since to be borrowed it must have been invented somewhere first. To solve this problem actual historical data are needed, something that is in most cases unattainable, but on the other hand, certain conclusions seem justifiable.
We note that many of the more material traits are peculiarly adapted to the bison-hunting life and to the habits of a semi-nomadic people. This seems reasonable, because many of them are rarely found outside of the Plains area. If this is granted, it seems proper to conclude that they must have been invented by some of the Plains group.
Another related problem is that of migration or origin. For the Cheyenne we have some historical data, the import of which seems to be that they migrated from the Woodlands to the Plains about two centuries ago, where they must have changed in culture very rapidly to become one of the typical tribes, as they were found to be in later years. It is also quite clear that the Sarsi, Plains-Cree and Plains-Ojibway came out of the northern and eastern forests into the Plains something more than two hundred years ago. As to other tribes, we have no data. There is ground for an assumption, however, in linguistic relationships. Some people say it will not do, for example, to say that the Algonkin tribes in the Plains migrated thither on the ground that the greater part of the stock lived in the Woodlands, for it is conceivable that the reverse may
